Seatbelts: A guide to safely resetting and recalibrating

May 8, 2017
In the unfortunate event of a collision, seatbelts help protect the occupants from injury, but what can be seen on the surface is just the beginning.
In the unfortunate event of a collision, seatbelts help protect the occupants from injury, but what can be seen on the surface is just the beginning. During a collision, the airbag computer initiates the seatbelt igniter to ignite, activating the seatbelts and locking them. Once seatbelts have been locked after a collision, they will need to be replaced, or repaired and reset.
Before the repair Seatbelts are designed to have a gas charge which ignites, locking the seatbelt. Regardless of whether it’s the seatbelt retractor, or the buckle pre-tensioner, once activated they will not work again. All seatbelt parts must be inspected before the repair is started. All locked and disabled seatbelts must be replaced to factory condition. The SRS airbag module may also need to be reset. Before beginning the repair, a pre-scan using the asTech™2 device will allow the technician to identify which diagnostic trouble code or codes were triggered so they can be reset. Once the scan is completed, the technician can then determine which parts will need to be replaced.Replacements and installation Every seatbelt retractor is equipped with a complex mechanism that is engineered to lock during a collision. The components are accompanied by a small explosive apparatus known as the inflator, which is triggered by the igniter, and must deploy in a timely matter. The entire process is all controlled by a small sensor that communicates with the airbag system in the vehicle. In the event of a collision that causes the system to deploy, the sensor, igniter and the inflator will all need to be completely replaced, in order to make the seatbelt operational once again. If the airbag warning light is on after the collision, the pre-tensioners, seat belt retractors, or buckles, will also need to be repaired or replaced.

Each seatbelt is equipped with at least one two-pronged sensor that connects to the plug. This sensor will activate the gas charge in the seatbelt that deploys it. A properly working sensor has a resistance between 2-3 Ohms. An improperly working sensor will either have no resistance, or will read something other than between 2-3 Ohms. If the resistance is not between 2-3 Ohms, it means that the sensor is working improperly, and must be replaced.

Once all of the parts have been replaced, it’s also recommended to do a completion scan with the asTech™2 device to ensure everything is properly working again after the repairs have been.

For more information about the proper repair of seatbelt mechanisms after a collision, or to find out more about the advantages of using theasTech™2 device, contact an asTech™ master technician today.

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